1. Field of the Invention
The present invention is directed to systems, methods, apparatus and related components that facilitate the installation of new detectors into legacy detector systems. More particularly, the invention relates to facilitating the conversion of zone-type heat, fire and/or smoke detector systems to addressable heat, fire and/or smoke detector systems. Accordingly, the general objects of the invention are to provide novel systems, methods and apparatus of such character.
2. Description of the Related Art
Heat, fire and smoke detectors/alarms have been widely installed in both commercial and residential structures to protect their inhabitants and other contents for many years. Since these building often last much longer than detector and alarm technologies, there are currently many older buildings that are equipped with technologically outdated protection systems. One particularly common protection system technology that has become outdated is that of the zone-type system. Since an understanding of zone-type systems is helpful in appreciating certain aspects of the present invention, however, a discussion of zone-type systems follows.
A representative zone-type protection system 10 is illustrated in FIG. 1. As shown therein, a conventional zone-type system uses plural heat, fire or smoke detectors 9, 9′ configured in a so-called detector loop 13 that terminates at and is electrically coupled to a control panel 11. In such a system, each detector loop 13 typically comprises plural wires (most often a pair of wires) that have been strung through various locations during the construction of a structure. Each detector loop is electrically coupled to a number of detectors 9, 9′ with an end-of-line resistor at one end and a control panel 11 to the other. A typical industrial zone-type system may include hundreds of detectors arranged in several zones (each of which may have one or more loops). Subsequent completion of the structure hides these loops from access except where the wiring is connected to a detector or control panel.
The detectors used in the above-noted systems are generally of the following three types: flame detector, thermal detector, or smoke detector. These three classes of detectors correspond to the three primary properties of a fire: flame, heat, and smoke and may be designed to sense smoke obscuration, ionization, temperature, or the like, all of which may be indicative of a fire. Conventional zone-type detector assemblies of the type used in the system 10 of FIG. 1, typically include a base 20 (as shown in FIG. 2) and a complementary detector (not shown). Conventional zone-type detector base 20 generally includes a body 21 with a detector-mating rim 25, at least two mounting apertures and a plurality of electrical terminals 22a through 22d. During installation of base 20, body 21 is affixed to the surface of a wired building via the mounting apertures and the detector loop wiring is hardwired to terminals 22a through 22d. For example, a pair wires from an incoming leg of a detector loop may be connected to terminals 22a and 22b as shown in FIG. 1 and as known in the art. Similarly a pair of wires for a downstream leg of the detector loop may be connected to terminals 22c and 22d as shown in FIG. 1 and as known in the art. It will be appreciated that the desired electrical circuitry will be completed by mating a conventional zone-type detector onto, now mounted, base 20 as is known in the art. In this way, each zone-type detector is electrically connected to the detector loop via the electrical connections within base 20.
A typical zone-type detector is designed to operate in an on/off mode by changing from an inactive state to an active state whenever the environmental condition that the detector is designed to monitor exceeds a predetermined threshold. In the active state, the internal resistance of the detector is lowered, thereby increasing the current flow through the detector loop. Control panel 11 provides the operating current for the detector loop and includes a current sensing mechanism communicatively linked to the detector loop. When the current flow level in the detector loop exceeds a predetermined threshold, control panel 11 activates an alarm and/or discharges a fire suppressant such as water, halon, etc. as is known in the art.
While such zone-type systems offer some advantages over older systems, one of their deficiencies was that they could only direct users' attention to the zone in which an emergency condition was detected (as opposed to the precise location of the detected emergency condition). This deficiency was solved with the introduction of more sophisticated detector systems with a control panel that is communicatively linked to microprocessor-based “addressable” detector assemblies of the type shown in exploded view in FIGS. 3a and 3b. As known, detector 12 preferably reports alarm conditions via radio transmission to a control panel.
Like zone-type detector assemblies 9, addressable detector assemblies 12 typically include a base 20′ and a complementary detector 30. Detector 30 includes electrical terminals 32a, 32b, 32c and 32d and a body with a rim 35. Base 20′ includes a body 21′ with a pair of surface mounting apertures and a rim 25′ designed to mate with rim 35 of detector 30. Base 20′ further includes electrical terminals 22a′, 22b′, 22c′ and 22d′. In use, terminals 22a′ through 22d′ are hardwired directly to detector loop wiring 13 and are also electrically coupled to respective terminals 32a through 32d of detector 30 as is known in the art.
Several examples of the above-discussed addressable detector assemblies include those in the “Signature Series” produced and sold by Edwards Systems Technology of Cheshire, Conn. under the designations “SIGA-PS,” “SIGA-AB4,” “SIGA-IB,” and “SIGA-RB.” Other examples of addressable detectors are well known in the art.
Addressable detectors of the type discussed above represent an advance in that each detector 12 has the ability to report its location when communicating the presence of an emergency condition. Further, they may produce signals that they are capable of indicating the magnitude of the parameters being sensed, rather than just active-inactive signals. The addressable system control panel, which is typically microprocessor-based and under software control, analyzes the information transmitted from detector assembly 12 to determine whether an alarm condition exists and, if so, where the reporting detector is located.
For these and other reasons, addressable systems have, essentially replaced zone-type systems in new installation applications. Additionally, many previously installed zone-type systems are being upgraded with addressable detectors and control panels specifically designed to retrofit zone-type systems. Since such retrofit systems utilize the legacy detector loop wiring 13 from the zone-type system 10, they are substantially less expensive than installation of a completely new addressable system.
In a typical retrofit application, addressable detector assembly 12 would be retrofit into a zone-type system by removing zone-type detector assembly 9′ and connecting base 20′ to the existing detector loop wiring 13. In particular, legacy detector assembly 9 would be disconnected from its associated legacy wiring 13 and removed from the building to which it was affixed. Addressable base 20′ is then affixed to a desired location (typically the same location as the newly removed zone-type base) and electrically connected to the, newly disconnected, legacy wiring 13. Further, addressable detector 30 is mated with addressable base 20′ such that detector 30 is electrically connected to the legacy detector loop wiring 13 via base 20′.
If necessary, one may manually disconnect an end of line device from the initiating circuit, to permit the existing circuit to accept new addressable devices. Often the location of this device is unknown, as it is traditionally mounted behind an existing device in the electrical junction box. Nonetheless, conventional retrofit applications sometimes require identification and removal of such end of line devices. This is normally a difficult and labor-intensive step.
Although retrofit applications of the nature described above are less expensive than new installations, they are still labor-intensive, complicated and expensive endeavors that rely heavily on skilled technicians. For example, most retrofit projects involve manual removal of every zone-type detector from its location and from its associated wiring, testing of the wiring leading throughout each zone and to each detector, diagnosis of certain wiring problems and/or conditions, and manual connection and affixation of the new addressable detectors. Among the most common of such problems are (1) reverse polarity wiring; (2) ground faults; and (3) a need to disconnect an end-of-line device. Furthermore, the facts that (1) every building is different; (2) a wide range of detector systems have been used throughout the years; and (3) customer preferences vary from project to project, make each retrofit project unique. Thus, installation decisions must be made on the fly and unanticipated problems solved during installation. It will be readily appreciated that highly skilled technicians are required to perform this complex set of tasks. Such technicians are costly, in short supply and difficult to train. It will also be appreciated that retrofit projects of the type discussed above necessarily interfere with normal operations of the buildings (typically housing businesses) in which they occur. It is, therefore, highly desirable to minimize the time for implementing retrofit upgrades.
There is, accordingly, a need in the art for improved methods, systems and apparatus to facilitate conversion of zone-type systems into addressable systems. In particular, such methods and apparatus should envision simplified apparatus and techniques for integrating addressable detectors into legacy zone-type system hardware. Such methods, systems and apparatus will ideally offer users/purchasers an optimal combination of (1) simplicity; (2) reliability; (3) economy; and (4) versatility.
There is a further need in that art for improved methods and apparatus for converting zone-type systems into addressable systems that are capable of solving a variety of common problems associated with retrofit installations such as (1) reverse polarity wiring; (2) ground faults; and (3) a need to disconnect an end-of-line device.